Buggy code:
public class CoreAdminHandler extends RequestHandlerBase { protected static Logger log = LoggerFactory . getLogger ( CoreAdminHandler . class ) ; protected final CoreContainer coreContainer ; public CoreAdminHandler ( ) { } public CoreAdminHandler ( final CoreContainer coreContainer ) { } @ Override public final void init ( NamedList args ) { } public CoreContainer getCoreContainer ( ) { } @ Override public void handleRequestBody ( SolrQueryRequest req , SolrQueryResponse rsp ) throws Exception { } protected void handleSplitAction ( SolrQueryRequest adminReq , SolrQueryResponse rsp ) throws IOException { } protected void handleMergeAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws Exception { } protected void handleCustomAction ( SolrQueryRequest req , SolrQueryResponse rsp ) { } public static ImmutableMap < String , String > paramToProp = ImmutableMap . < String , String > builder ( ) . put ( CONFIG , CORE_CONFIG ) . put ( SCHEMA , CORE_SCHEMA ) . put ( DATA_DIR , CORE_DATADIR ) . put ( ULOG_DIR , CORE_ULOGDIR ) . put ( LOAD_ON_STARTUP , CORE_LOADONSTARTUP ) . put ( TRANSIENT , CORE_TRANSIENT ) . put ( SHARD , CORE_SHARD ) . put ( COLLECTION , CORE_COLLECTION ) . put ( ROLES , CORE_ROLES ) . put ( CORE_NODE_NAME , CoreDescriptor . CORE_NODE_NAME ) . put ( SHARD_STATE , CloudDescriptor . SHARD_STATE ) . put ( SHARD_RANGE , CloudDescriptor . SHARD_RANGE ) . put ( NUM_SHARDS_PROP , NUM_SHARDS ) . build ( ) ; public static ImmutableMap < String , String > cloudParamToProp ; protected static CoreDescriptor buildCoreDescriptor ( SolrParams params , CoreContainer container ) { String name = CoreAdminHandler . checkNotEmpty ( params . get ( NAME ) , ( ( "Missing<seq2seq4repair_space>parameter<seq2seq4repair_space>[" + ( CoreAdminParams . NAME ) ) + "]" ) ) ; String instancedir = params . get ( INSTANCE_DIR ) ; if ( StringUtils . isEmpty ( instancedir ) ) { instancedir = name ; } Properties coreProps = new Properties ( ) ; for ( String param : CoreAdminHandler . paramToProp . keySet ( ) ) { String value = params . get ( param , null ) ; if ( StringUtils . isNotEmpty ( value ) ) { coreProps . setProperty ( CoreAdminHandler . paramToProp . get ( param ) , value ) ; } } Iterator < String > paramsIt = params . getParameterNamesIterator ( ) ; while ( paramsIt . hasNext ( ) ) { String param = paramsIt . next ( ) ; if ( ! ( param . startsWith ( PROPERTY_PREFIX ) ) ) continue ; String propName = param . substring ( PROPERTY_PREFIX . length ( ) ) ; String propValue = params . get ( param ) ; coreProps . setProperty ( propName , propValue ) ; } <START_BUG> return new CoreDescriptor ( container , name , instancedir , coreProps ) ; <END_BUG> } private static String checkNotEmpty ( String value , String message ) { } protected void handleCreateAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws SolrException { } protected void handleRenameAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws SolrException { } @ Deprecated protected void handleAliasAction ( SolrQueryRequest req , SolrQueryResponse rsp ) { } protected void handleUnloadAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws SolrException { } protected void handleStatusAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws SolrException { } protected void handlePersistAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws SolrException { } protected void handleReloadAction ( SolrQueryRequest req , SolrQueryResponse rsp ) { } protected void handleSwapAction ( SolrQueryRequest req , SolrQueryResponse rsp ) { } protected void handleRequestRecoveryAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws IOException { } protected void handleRequestSyncAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws IOException { } protected void handleWaitForStateAction ( SolrQueryRequest req , SolrQueryResponse rsp ) throws IOException , InterruptedException , KeeperException { } private void handleRequestApplyUpdatesAction ( SolrQueryRequest req , SolrQueryResponse rsp ) { } protected NamedList < Object > getCoreStatus ( CoreContainer cores , String cname , boolean isIndexInfoNeeded ) throws IOException { } private long getIndexSize ( SolrCore core ) { } protected static String normalizePath ( String path ) { } public static ModifiableSolrParams params ( String ... params ) { } @ Override public String getDescription ( ) { } @ Override public String getSource ( ) { } }

Fix:
return new CoreDescriptor ( container , name , instancedir , coreProps , params ) ;